Method and apparatus for conducting offshore drilling operations



Aug 25, I964 s. D. MCCARTY 3 14 METHOD AND APPARATUS FOR CONDUCTING OFFSHORE 5775 DRILLING OP Filed Jan. 50, 1958 ERATIONS 6 Sheets-Sheet 1 BLOCK SWIVEL FIG. 2.

23 ROTARY INVENTOR.

SHILE D- McCARTY,

AT TORNEY.

Aug. 25, 1964 s. D. M CARTY 3,145,775

METHOD AND APPARATUS FOR CONDUCTING OFFSHORE DRILLING OPERATIONS Filed Jan. 30, 1958 6 Sheets-Sheet 2 FIG. 6. FIG. 4.

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SHILE D. McCARTY,

A TTORNEY.

Aug. 25, 1964 D MCCARTY 3,145,775

, S. METHOD AND APPARATUS FOR CONDUCTING OFFSHORE DRILLING OPERATIONS Filed Jan. 30, 1958 6 Sheets-Sheet 3 sz L A 32 ai INVENTOR.

ATTORNEY Aug. 25, 1964 METHOD AND APPARA Filed Jan. 30, 1958 S D. M CARTY TUS FOR CONDUCTING OFFSHORE DRILLING OPERATIONS 6 Sheets-Sheet 4 FIG. I2. 44

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SH l LE D. McCARTY,

AAA/J ATTORNEY.

Aug. 25, 1964 s. D. M CARTY 3,145,775

METHOD AND APPARATUS FOR CONDUCTING OFFSHORE DRILLING OPERATIGNS Filed Jan. 30, 1958 6 Sheets-Sheet 5 FIG. l4.

INVENTOR.

SHILE D. McCARTY,

ATTORNEY.

Aug. 25, 1964 s. D. M CARTY 3,145,775

METHOD AND APPARATUS FOR CONDUCTING OFFSHORE DRILLING OPERATIGNS Flled Jan. 30, 1958 6 Sheets-Sheet 6 FIG. I7.

2O 20 F? 2| 23 g 5 SHILE D. MCCARTY ATTORNEY- United States Patent 3,145,775 METHOD AND APPARATUS FOR CONDUCTING OFFSHDRE DRILLING ()PERATIONS Shile D. McCarty, Los Angeles, Calif., assignor to Jersey Production Research Company, Tulsa, Okla, a corporation of Delaware Filed Jan. 30, 1958, Ser. No. 712,106 5 Claims. (Cl. 16646) This invention relates to methods and apparatus for conducting offshore drilling operations.

When conducting drilling operations or working on under-water wells from an oifshore structure, relocating a particular well is made diflicult by forces such as winds, tides, waves, and currents which cause movement of the oifshore structure or string of pipe extending therefrom or both.

Methods and means for insuring re-entry into submarine wells are necessary. For example, during drilling operations when it is desired to change the size of or replace an underreamer or bit, the drill string must be pulled completely out of the borehole and then returned thereto after the desired change has been made. Techniques and equipment must be provided to insure such re-entry.

Another dilficulty in conducting offshore operations concerns return circulation of drilling fluid. In conventional drilling practice in land locations the drilling fluid is circulated down the drill pipe and up the annulus between the borehole wall and the drill pipe to the surface of the earth where cuttings are removed before recirculating the drilling fluid again down the drill pipe whereas in oifshore operations conducted from an offshore structure the drilling fluid must be circulated not only to the surface of the earth but also to the offshore structure prior to recirculation down the drill pipe.

Although the above-noted difiiculties are more pronounced when conducting operations from a floating structure than when conducting operations from a stationary offshore structure the present invention is designed to overcome these difiiculties whether the operations structure is stationary or floating.

Thus, an object of this invention is to provide methods and apparatus for facilitating re-entry into a borehole and for providing for the return circulation of drilling fluid to the offshore structure.

Briefly, the invention comprises a method for conducting olfshore drilling operations utilizing an offshore structure, drill pipe, casing pipe, and conductor pipe, the pipes being concentrically arranged which includes the steps of suspending the casing and conductor pipes from the offshore structure, then drilling a borehole and during said drilling maintaining at least one of said pipes in said borehole when manipulating said pipes for said drilling and maintaining at least one of said pipes in said borehole when manipulating said pipes din-ing any other operations.

The invention includes two embodiments of this method. In one embodiment the conductor pipe and the casing pipe are initially suspended together, the drill pipe being separately suspended from the offshore structure. In the other embodiment, the drill pipe, the casing pipe, and the conductor pipe are each separately suspended initially from the offshore structure.

The invention also contemplates apparatus comprising an oifshore structure having suspended therefrom drill pipe, casing pipe, and conductor pipe concentrically arranged, the lower end of the drill pipe being arranged adjacent to and above the land underlying the water when a drilling operation is initiated and wherein at least one of said pipes is positioned in the borehole at all times after drilling operations have started.

7 3,145,775 Patented Aug. 25, 1964 ice The above object and other objects of the invention will be apparent from the following description of the invention taken in conjunction with the drawings wherein:

I FIGS. 1 through 14 show the apparatus of the invention and the sequential steps of one embodiment of the method of the invention; and

FIGS. 15 through 17 show the apparatus of the invention and a part of the sequential operation of another embodiment of the method of the invention.

For a more complete description of the invention, reference to the drawings in greater detail will now be made.

In FIG. 1 is shown an offshore drilling structure, such as a barge 10. positioned on the surface of water 11 and having a cellar 12 formed therein through which drilling operations are conducted. A drilling platform 14 is positioned on barge ltl. A conductor pipe 17 provided with a bracket 18 at the upper end thereof is suspended in cellar 12 by means of cables 19 connected to motor hoists 21 which hoists are adapted to pay out and reel in cables 19. To provide additional support, if desired, turn-buckles 21 may be used to connect conductor pipe 17 to barge 10. As seen in FIG. 1, a casing pipe 22 is being lowered through conductor pipe 17 by means of elevators 23.

Casing pipe 22 is lowered through and landed on top of conductor pipe 17, as seen in FIG. 2. The lower end of easing pipe 22 extends into the water to a desired distance above the ocean floor 15, which is a distance sufficient to accommodate vertical movement of barge 10. A rotary 30 is positioned above cellar 12 and a string of drill pipe 31 provided with a drill bit 32 and an underreamer 33 is lowered through casing pipe 22 until the lower end of the bit extends below the lower end of casing pipe 22, as shown in FIG. 2. A kelly joint 34 is then connected to the upper end of drill string 31 and to a swivel, hook, and block, as shown.

A borehole 35 then is drilled, as seen in FIG. 3', the kelly joint being moved downwardly and drill bit 32 and underreamer 33 being advanced a suflicient distance to make a portion of the hole for conductor pipe 17. Condnctor pipe 17 and easing pipe 22 are maintained stationary during this operation.

To proceed with further drilling, additional drill pipe must be added which requires raising of the kelly-drill pipe connection to above rotary 3t). Raising of the drill pipe from the borehole to make this kelly-drill pipe connection would cause removal of the drill pipe from the borehole and thus make re-entry into the borehole very difficult and probably impossible. Accordingly, turn-buckles 21 are disconnected from bracket 18 of conductor pipe 17. Conductor pipe 17 and easing pipe 22 supported thereby are lowered together by means of cables 19 and hoists 20 until the lower end of easing pipe 22 is positioned in borehole 35, as illustrated in FIG. 4. Drill pipe 31 now may be withdrawn from borehole 35 since casing pipe 22- facilitates re-entry of drill pipe 31 into borehole 35.

Drill pipe 31 then is pulled up until the upper end of drill pipe 31 is positioned above rotary 30 in order to add additional pipe to the upper end of drill pipe 31, as seen in FIG. 5. The lower end of drill pipe 31 is inside casing pipe 22, as shown.

A new joint of drill pipe and kelly 34 are connected to drill pipe 31. Drill pipe 31 then is lowered back into borehole 35 until bit 32 is positioned on the bottom of the borehole, as shown in FIG. 6.

Drilling fluid then is circulated down drill pipe 31 and during this operation conductor pipe 17 and casing pipe 22 supported thereby are raised by cables 19 and hoists 20 back to the original position of these pipes, as shown in FIG. 7.

As seen in FIG. 8, new joints of drill pipe 31 are added as required and borehole 35 is drilled to a depth suflicient to permit setting of conductor pipe 17 therein. These new joints are added while the lower end of drill pipe 31 is maintained in borehole 35.

New sections of casing pipe 22 must now be added. To do this, as seen in FIG. 9, drill pipe 31 is raised while maintaining the lower portion thereof in borehole 35 and slips 36 are set on drill pipe 31. Kelly joint 34 is disconnected from drill pipe 31 and an eye-sub 41 is connected to the upper end of drill pipe 31 a substantial distance above rotary 30. A new section of easing pipe 22 then is stripped over the upper end of drill pipe 31.

As seen in FIG. 10, a cable 43 is connected to sub 41 to support drill pipe 31. With the weight of drill pipe 31 supported by cable 43, drill pipe slips 36 are removed and casing pipe 22 is lowered by means of elevators 44 and connected to casing pipe 22 in cellar 12. Elevators 23 then are removed.

As seen in FIG. 11, additional casing pipe 22 is connected in accordance with the method described with regard to FIGS. 9 and 10 until the lower end of easing pipe 22 extends a selected distance into borehole 35. As shown, at this time, casing pipe 22 is supported in cellar 12 by elevators 44 and turn-buckles 21.

As shown in FIG. 12, conductor pipe 17 including bracket 18 is lowered into borehole 35 by means of cables 19 until bracket 18 is positioned adjacent ocean floor 15. During this operation, drill pipe 31 is supported from barge 10 by means of drill pipe slips 36. After conductor pipe 17 has been positioned in borehole 35, cable 43 and eye-subs 41 are disconnected and drill pipe 31 is completely Withdrawn from borehole 35 and casing pipe 22. At this time casing pipe 22 extends from barge 10 into conductor pipe 17 which insures re-entry of drill pipe 31 into conductor pipe 17. Underreamer 32 is replaced by a smaller underreamer 50. Drill pipe 31 is lowered back into borehole 35 through casing pipe 22 and conductor pipe 17. The kelly joint 34 with connected swivel and block is again connected to drill pipe 31 and borehole 35 is deepened to accommodate casing pipe 22.

Drill pipe 31, underreamer 50 and bit 32 then are removed completely from borehole 35 and casing pipe 22. Additional casing pipe 22 is added and then additional casing pipe 22 is lowered into borehole 35.

Controlling equipment 60 including lower controlling equipment 60a and upper controlling equipment 60b is connected to the upper end of easing pipe 22. Casing pipe 22 then is lowered into position, as shown in FIG. 13.

Lower controlling equipment 60a includes a ram type blowout preventer 61, a sleeve type blowout preventer 62, a drilling head 63 provided with suitable locking means therein and a mud return line 64. This equipment is preferably hydraulically operated. Such hydraulic installations are conventional and desirable for submerged locations since by suitable hose connections, not shown, the equipment may be remotely operated from the structure located at the surface of the water.

Upper controlling equipment 60b includes a locking sub 65, a flexible joint 66, a slip joint 67, a drilling head 68 provided with a funnel guide 69, and a conduit 70. Locking sub 65 of upper controlling equipment 60b releasably locks with the locking means contained in drilling head 63 of lower controlling equipment 60a.

The controlling equipment 60 may be that such as is shown and described in US application Serial Nos. 671,000, entitled Offshore Apparatus by W. F. Hiser and S. D. McCarty, filed July 10, 1957, and 671,078, entitled Adapter by C. M. Carothers and L. M. Harris, filed July 10, 1957.

The upper end of controlling equipment 6% is supported in cellar 12 by means of turn-buckles 21.

The open ended drill pipe 31 is lowered through controlling equipment 60 and casing pipe 22 until the lower end thereof is positioned adjacent the lower end of casing pipe 22. Casing pipe 22 then is cemented in position in borehole 35 by flowing a cement slurry down drill pipe 31 and up the annulus surrounding casing pipe 22.

After cementing in casing pipe 22, drill pipe 31 is pulled, drill bit 32 is positioned on drill pipe 31, and drill pipe 31 is lowered back into the borehole. The borehole then is drilled to any desired depth. During this drilling, the circulation system for the drilling fluid is down drill pipe 31 and out the lower end thereof, up the annulus between the borehole wall and drill pipe 31, through the annulus between casing pipe 22 and drill pipe 31, through the controlling equipment 60, and out conduit 70 for recirculation. All re-entry to the well is made through funnel 69 of controlling equipment 60.

After the borehole has been drilled to the desired total depth, the apparatus may be removed from the well. One manner of removing this apparatus, as seen in FIG. 14, is to remove drill pipe 31 and shoot-off casing pipe 22 and conductor pipe 17 in borehole 35. The controlling equipment 60 and attached casing pipe 22 are removed. Conductor pipe 17 is removed by means of cables 19.

The alternate procedure is shown in FIGS. 15 through 17. The apparatus is similar; however, in the initial arrangement of equipment casing pipe 22 and conductor pipe 17 are independently suspended in cellar 12 prior to initiation of drilling. Thus, conductor pipe 17 is suspended on cables 19 attached to hoists 20 and casing pipe 22 is connected to barge 10 by means of turn-buckles 21.

As seen in FIG. 16, a portion of the borehole has been drilled for conductor pipe 17. This is similar to the step shown in FIG. 3.

The lower end of conductor pipe 17 is positioned in the borehole, as seen in FIG. 17. Drill pipe 31 is lengthened and suficient borehole is drilled to accommodate conductor pipe 17. Drill pipe 31 then is removed from within casing pipe 22 and additional lengths of casing pipe 22 are added to insure that the lower end of casing pipe 22 extends into the borehole. Conductor pipe 17 then is lowered to the desired setting depth. Drill pipe 31 then is run as in FIG. 12. The remaining steps are the same as those previously described and illustrated in FIGS. 13 and 14.

Methods described herein relate primarily to drilling operations conducted from an olfshore structure wherein concentric pipes are suspended from the olfshore structure and wherein at least one of these pipes extends into the borehole from the offshore structure at all times after drilling has commenced. Operations other than those described herein are within the scope of this invention such as, for example, cementing in the conductor pipe. The only criterion is that at least one pipe extends into the borehole from the olfshore structure at all times in order to maintain communication with and facilitate entry into the borehole.

Having fully described the nature, objects, and operation of the invention, I claim:

1. A method for conducting offshore drilling operations in which a borehole is formed in the ground underlying water by rotating a drilling tool attached to the lower end of drill pipe while circulating drilling fluid through the drilling tool and drill pipe comprising the steps of: suspending open ended conductor and casing pipes from an offshore drilling structure, the upper ends of said conductor and easing pipes being initially positioned above the water level, said casing pipe being of smaller diameter than said conductor pipe and being adapted to extend into and through said conductor pipe, said casing pipe being initially suspended in a manner such that it extends through said conductor pipe with its lower end positioned adjacent the ground underlying the water; lowering a drill pipe of smaller diameter than said casing pipe and suspended from said offshore structure through said casing pipe in a manner such that it extends through said casing pipe with its lower end positioned adjacent the ground underlying the water; forming a borehole in the ground underlying the water of a diameter suflicient to accommodate said conductor pipe with a rotating drilling tool attached to the lower end of said drill pipe to a selected depth, said drill pipe moving into said borehole as it is being drilled; lowering one of said pipes other than said drill pipe into said borehole; continuing forming said borehole of a diameter sufficient to accommodate conductor pipe to a deeper selected depth with a rotating drilling tool attached to the lower end of said drill pipe; lowering said conductor pipe into said borehole; continuing forming said borehole of a diameter only sufficient to accommodate casing pipe to a deeper selected depth with a rotating drilling tool attached to the lower end of said drill pipe; lowering said casing pipe into said borehole; and then continuing forming said borehole of a diameter only sufficient to accommodate drill pipe to a deeper desired depth with a rotating drilling tool attached to the lower end of said drill pipe; and during said forming of said borehole to accommodate said conductor and casing pipes which operation includes removing the lower end of said drill pipe and the lower end of said casing pipe from said borehole and adding sections of drill pipe and easing pipe maintaining at least one of said pipes in said borehole.

2. A method as recited in claim 1 including conducting said operations from a floating offshore structure.

3. A method for conducting offshore drilling operations in which a borehole is formed in the ground underlying water by rotating a drilling tool attached to the lower end of drill pipe While circulating drilling fluid through the drilling tool and drill pipe comprising the steps of: suspending open-ended conductor and casing pipes from an ofishore drilling structure, the upper ends of said conductor and casing pipes being initially positioned above the water level, said casing pipe being of smaller diameter than said conductor pipe and being adapted to extend into and through said conductor pipe, said casing pipe being initially suspended in a manner such that it extends through said conductor pipe with its lower end positioned adjacent the ground underlying the water; lowering a drill pipe of smaller diameter than said casing pipe and suspended from said offshore structure through said casing pipe in a manner such that it extends through said casing pipe with its lower end positioned adjacent the ground underlying the water; forming a borehole in the ground underlying the water of a diameter sufficient to accommodate said conductor pipe with a rotating drilling tool attached to the lower end of said drill pipe to a selected depth, said drill pipe moving into said borehole as it is being drilled; lowering said conductor and casing pipes together until said casing pipe extends into said borehole; raising said drill pipe in order to add length thereto until the lower end thereof is removed from said borehole; adding drill pipe length; lowering said drill pipe until the lower end thereof is again positioned in said borehole; raising said conductor and casing pipes together to their initial positions; forming said borehole of a diameter sufiicient to accommodate said conductor pipe to a deeper selected depth with a rotating drilling tool attached to the lower end of said drill pipe during which additional length of drill pipe may be added; raising said drill pipe in order to increase the length of said casing pipe while maintaining a portion of said drill pipe in said borehole; adding additional length of casing pipe; lowering said casing pipe until the lower end thereof is positioned in said borehole; lowering said conductor pipe into said borehole until the lower end thereof is positioned at said deeper selected depth; forming said borehole of a diameter only sufficient to accommodate said casing pipe to an additional deeper selected depth with a rotating drilling tool attached to the lower end of said drill pipe; lowering said casing pipe in said borehole until the lower end thereof is positioned at said additional deeper selected depth and connecting control equipment which includes a conduit extending from adjacent the ground underlying the water to the water surface when said casing pipe is arranged in the borehole to said casing pipe during the course of positioning the lower end of said casing pipe at said deeper selected depth; and then forming said borehole of a diameter only sufficient to accommodate drill pipe to any desired depth with a rotating drilling tool attached to the lower end of said drill pipe, the various steps following initial penetration of the drill pipe into the ground underlying the water until connection of the control equipment to said casing pipe being performed while at least one of said pipes extends from said offshore structure into said borehole.

4. A method as described in claim 3 including removing said drill pipe from said borehole, disconnecting the upper portion of said casing pipe from the lower portion thereof in said borehole, removing said control equipment and the upper portion of the casing pipe connected thereto from said borehole, and removing said conductor pipe from said borehole.

5. A method for conducting offshore drilling operations in which a borehole is formed in the ground underlying water by rotating a drilling tool attached to the lower end of drill pipe while circulating drilling fluid through the drilling tool and drill pipe comprising the steps of: suspending open-ended conductor and casing pipes from an oifshore drilling structure, the upper ends of said conductor and casing pipes being initially positioned above the Water level, said casing pipe being of smaller diameter than said conductor pipe and being adapted to extend into and through said conductor pipe, said casing pipe being initially suspended in a manner such that it extends through said conductor pipe with its lower end positioned adjacent the ground underlying the water; lowering a drill pipe of smaller diameter than said casing pipe and suspended from said offshore structure through said casing pipe in a manner such that it extends through said casing pipe with its lower end positioned adjacent the ground underlying the water; form ing a borehole in the ground underlying the water of a diameter suflicient to accommodate said conductor pipe with a rotating drilling tool attached to the lower end of said drill pipe to a selected depth, said drill pipe moving into said borehole as it is being drilled; lowering said conductor pipe until the lower end thereof is positioned in said borehole; raising said drill pipe in order to add length thereto until the lower end thereof is removed from said borehole; adding drill pipe length, lowering said drill pipe until the lower end thereof is positioned in said borehole; forming said borehole of a diameter sufiicient to accommodate said conductor pipe to a deeper selected depth with a rotating drilling tool attached to the lower end of said drill pipe during which additional length of drill pipe may be added; raising said drill pipe while maintaining a portion thereof in said borehole in order to increase the length of said casing pipe; adding additional length of casing pipe; lowering said casing pipe until the lower end thereof is positioned in said bore hole; lowering said conductor pipe into said borehole until the lower end thereof is positioned at said deeper selected depth; forming said borehole of a diameter only sufficient to accommodate said casing pipe to an additional deeper selected depth with a rotating drilling tool attached to the lower end of said drill pipe; lowering said casing pipe in said borehole until the lower end thereof is positioned at said additional deeper selected depth and connecting control equipment which includes a conduit extending from adjacent the ground underlying the Water to the water surface when said casing pipe is arranged in the borehole to said casing pipe during the course of positioning the lower end of said casing pipe at said deeper selected depth; and then forming said borehole of a diameter only sufficient to accommodate drill pipe to any desired depth with a rotating drilling tool attached to the lower end of said drill pipe, the various steps following initial penetration of the drill pipe into the ground underlying the Water until connection of the control equipment to said casing pipe being performed while at least one of said pipes extends from said oifshore structure into said borehole.

References Cited in the file of this patent UNITED STATES PATENTS lanes et al Sept. 25, 1883 8 Grace et a1. Apr. 13, 1937 Laurie Apr. 22, 1941 Tucker June 27, 1950 McNeill Aug. 5, 1952 Bauer et a1 Oct. 1, 1957 Bauer et al June 23, 1959 Bauer et al. Oct. 20, 1959 Bauer et a1. Feb. 2, 1960 Stratton Mar, 22, 1960 

1. A METHOD FOR CONDUCTING OFFSHORE DRILLING OPERATIONS IN WHICH A BOREHOLE IS FORMED IN THE GROUND UNDERLYING WATER BY ROTATING A DRILLING TOOL ATTACHED TO THE LOWER END OF DRILL PIPE WHILE CIRCULATING DRILLING FLUID THROUGH THE DRILLING TOOL AND DRILL PIPE COMPRISING THE STEPS OF: SUSPENDING OPEN ENDED CONDUCTOR AND CASING PIPES FROM AN OFFSHORE DRILLING STRUCTURE, THE UPPER ENDS OF SAID CONDUCTOR AND CASING PIPES BEING INITIALLY POSITIONED ABOVE THE WATER LEVEL, SAID CASING PIPE BEING OF SMALLER DIAMETER THAN SAID CONDUCTOR PIPE AND BEING ADAPTED TO EXTEND INTO AND THROUGH SAID CONDUCTOR PIPE, SAID CASING PIPE BEING INITIALLY SUSPENDED IN A MANNER SUCH THAT IT EXTENDS THROUGH SAID CONDUCTOR PIPE WITH ITS LOWER END POSITIONED ADJACENT THE GROUND UNDERLYING THE WATER; LOWERING A DRILL PIPE OF SMALLER DIAMETER THAN SAID CASING PIPE AND SUSPENDED FROM SAID OFFSHORE STRUCTURE THROUGH SAID CASING PIPE IN A MANNER SUCH THAT IT EXTENDS THROUGH SAID CASING PIPE WITH ITS LOWER END POSITIONED ADJACENT THE GROUND UNDERLYING THE WATER; FORMING A BOREHOLE IN THE GROUND UNDERLYING THE WATER OF A DIAMETER SUFFICIENT TO ACCOMMODATE SAID CONDUCTOR PIPE WITH A ROTATING DRILLING TOOL ATTACHED TO THE LOWER END OF SAID 